How to Fight the 6 Most Common Types of Algae in Your Fish Tank (2022)

Do you dream of having a beautiful aquarium but end up constantly fighting to keep algae at bay? It’s a familiar struggle that many of us have been through, so in this article, let’s get a better understanding of the root causes of algae, the most common types found in freshwater aquariums, and how to gain the upper hand.

Is Algae Bad for a Fish Tank?

Contrary to popular belief, algae are not evil. Like plants, they use photosynthesis to convert light and organic nutrients in the water (such as fish waste) into new algae growth. That means they also produce oxygen during the daytime and consume it at night. Unlike plants, algae are a less complex lifeform and therefore can survive in “worse” conditions than plants, meaning they can absorb more wavelengths of light and consume different compounds that plants can’t use.

Algae is actually a good thing for your aquarium’s ecosystem because many fish and invertebrates like to eat it and it helps clean the water as a form of filtration. Plus, certain algae can look attractive and make an aquarium seem more natural. However, most people don’t like their appearance, especially in planted tanks, since it blocks the scenery and viewing area in a fish tank.

The reality is that there is no such thing as a perfect planted aquarium that is 100% free of algae. Imagine you have a neighbor with a well-groomed lawn of grass. Even they will get the occasional weed (like algae in an aquascape) that must be dealt with. Now let’s suppose your not-as-nice lawn has five dandelion weeds that have grown to one foot tall. If you mow the lawn, then it will appear as if you have no weeds. In the same way, we want to learn how to appropriately control algae so that you can’t see it and the tank looks like practically spotless.

Why Does My Fish Tank Have So Much Algae?

Algae is caused by an imbalance of nutrients and lighting in your aquarium. This simple statement can be a little difficult to unpack, but basically, your plants need just the right amount of lighting and nutrients for optimal growth. If you give them too much light and not enough nutrients as building blocks to grow, the algae will take advantage of the excess light and multiply. If you provide a lot of nutrients but not enough light (which regulates how fast plants can utilize the nutrients), then algae will take advantage of the extra nutrients. To make matters worse, achieving a perfectly balanced tank is nearly impossible because even if you balance everything today, your plants will continuously grow or you will prune them, thus changing the amount of nutrients and lighting they need.

How Do I Get Rid of Algae in My Fish Tank?

Since you will always have some imbalance between lighting and nutrients, the goal is to get your aquarium as close to being balanced as possible, and then use an algae-eating crew to fill in the rest of the gap. We have found this one-two punch strategy quite effective at greatly reducing algae to unnoticeable amounts. In the following section, we’ll be discussing thesix most common types of aquarium algae with targeted tactics of dealing with them.

(Video) Complete Algae Beginners Guide - Learn ALL The Basics Of The Most Common Types Of Aquarium Algae

Brown Diatom Algae

Brown (and sometimes green) diatom looks like a dusty, flour-like substance covering your aquarium walls, substrate, and other surfaces. Because it’s so soft, it easily rubs off with an algae scrubber sponge, and many animals (like otocinclus catfish, snails, and shrimp) like to eat it. Diatom algae is most commonly seen in newly planted tanks and is often caused by high levels of phosphates and silicates. It’s one of the simplest algae to get rid of because if you just give it some time, the plants will naturally consume the excess phosphates and silicates, and clean-up crews love to feed on it.

How to Fight the 6 Most Common Types of Algae in Your Fish Tank (1)

Brown algae

Black Beard Algae (BBA)

BBA is one of the most problematic algae that people run into because not many things eat it. As per its name, it grows in very thick, bushy clumps that are usually black or grey in color (but sometimes reddish or brownish). This algae likes to grow on driftwood, aquarium decor, and plants, and if left unchecked, it can completely engulf an aquarium in one to two years. Unfortunately, there’s a lot of different things that can contribute the growth of BBA, so there’s no one simple way to treat it.

How to Fight the 6 Most Common Types of Algae in Your Fish Tank (2)

Black beard algae

(Video) How to Get Rid of Aquarium Algae​ | Causes, Different Types, & Algae Eaters

If you don’t like the look of the algae, you can try adding Siamese algae eaters, Florida flagfish, or amano shrimp (although the shrimp take a long time to eat it unless you have an army of them). Some people turn to chemical treatments, such as using liquid carbon to directly spray on the BBA for tough cases or to dose the entire aquarium’s water column for mild cases. Just be careful because certain plants like vallisneria are sensitive to liquid carbon.

Another chemical treatment is to spray the BBA-infested plant or decor with 3% hydrogen peroxide (purchased from your local drugstore) outside of water, let it sit for 5 minutes, rinse off the chemical, and put the item back in the aquarium. The dying algae turns red or clear, and animals may eat it in its weakened state. Just remember that there are no quick fixes – BBA can take six to eight months to get established, so expect it to take at least that long to get rid of.

Hair Algae

In this category, we’re referring to the many types of algae that look like wet hair when you take them out of the aquarium (e.g., hair algae, staghorn algae, string algae, and thread algae). These algae can be problematic because they grow so rapidly or are hard to get rid of. They’re generally caused by an excess of certain nutrients (such as iron), too much light, or not enough nutrients (to match the long lighting period). Therefore, try decreasing your lighting period, increasing fertilization, or decreasing iron. Siamese algae eaters, amano shrimp, molly fish, and Florida flagfish are good candidates to use as clean-up crew. You can also help them by manually removing large clumps using a toothbrush.

How to Fight the 6 Most Common Types of Algae in Your Fish Tank (3)

Hair algae

Green Spot Algae (GSA)

GSA looks like tiny, hard green spots on the aquarium walls and slower growing plants that are very difficult to clean off. A lot of things can cause an outbreak, such as too much light or an imbalance of phosphate. Try using a glass-safe or acrylic-safe algae scraper (with the blade attachment) to remove the algae from aquarium walls.

(Video) How To DESTROY Algae in 30 Seconds (Get Rid Of Aquarium Algae FAST)

Nerite snails are also a good first line of defense since they seem to like eating GSA. Just be aware that, while this species does not reproduce in freshwater aquariums, they will lay white eggs (similar to little sesame seeds) all over the aquarium, and some people don’t like the look.

How to Fight the 6 Most Common Types of Algae in Your Fish Tank (4)

Nerite snail eating green spot algae

Blue-Green Algae (BGA)

BGA is technically not a type of algae, but rather a cyanobacteria that grows like a slimy blanket coating the substrate, plants, and decor. It comes with a rather distinctive smell that many fish keepers learn to recognize before the bacterial colony is even visible.No one is 100% sure what causes BGA, but in general, improved aquarium upkeep and increased water circulation with an air stone or powerhead can help keep it away. Algae eaters typically will not eat the stuff, so don't count on their help in this case.

How to Fight the 6 Most Common Types of Algae in Your Fish Tank (5)

Blue-green algae or cyanobacteria

(Video) The Different Kinds of Algae in a Freshwater Aquarium

Since BGA is photosynthetic, you can try to blackout the tank for a week, but this can be hard on the plants. Instead, we recommend manually removing as much of the BGA as possible, doing a water change while vacuuming the substrate, and then treating the tank with antibiotics. Use one packet of Maracyn (which is made of an antibiotic called erythromycin) per 10 gallons of water, and let the aquarium sit for one week before doing another water change. Repeat the treatment one more time for stubborn cases. For more information on treating BGA, read our full article here.

Green Water

If your aquarium water looks like pea soup, you probably have green water, which is caused by a proliferation of free-floating, single-celled phytoplankton. Unfortunately, they replicate so quickly that you cannot flush them out with large water changes. Green water can come from too much lighting (especially if the tank gets direct sunlight sometime during the day), an excess of nutrients (such as accidentally double-dosing fertilizers), or an ammonia spike (such as from a new tank that has not been cycled yet or overfeeding by a pet sitter). To get rid of green water, you can blackout the tank for at least a week, which is hard on your plants. Another option is to purchase a UV sterilizer, which will kill off the algae within two to three days.

How to Fight the 6 Most Common Types of Algae in Your Fish Tank (6)

Green water

How to Balance Lighting and Nutrients

When it comes to fighting algae, everyone always assumes you must decrease lighting and/or nutrients, but sometimes the better course of action is to increase one or both of them. Let’s go back to our example where you have a green lawn with five dandelions. It doesn’t make sense to stop watering your lawn (e.g., stop using lighting and fertilizers) just to get rid of a few weeds because you’ll probably end up killing your grass too. Instead, we deal with the weeds by pulling them out (e.g., manually removing the algae or getting a snail to eat them) and/or feeding the lawn more so that it’s healthier and the weeds won’t come back as readily.

Your focus should be on successfully growing lots of plants, not necessarily on eliminating algae at all costs. To balance the aquarium, put your light on an outlet timer as a constant factor, and then gradually increase or decrease your nutrient levels with an all-in-one fertilizer. Do not make multiple or drastic changes all at once because it takes at least two to three weeks to see any difference in your plants and determine whether or not your actions helped balance the aquarium. (For more detailed troubleshooting steps, see our plant nutrient deficiency article to learn which specific nutrients your plants might be missing.)

(Video) Top 5 Tips for Beating ALGAE in Your Fish Tank!

The Internet claims that if you do everything perfectly, your tank will never get algae, but in our experience, this is highly unlikely in the real world. Even Takashi Amano, known as the father of modern aquascaping, popularized the usage of the algae-eating amano shrimp to keep his planted tanks clean and beautiful. So, don’t be afraid to bring in the right algae eaters to help out while you’re trying to fix your lighting and nutrient balance issues. Best of luck on your plant-keeping journey!

FAQs

How do you fight algae in a tank? ›

Using a solution of 5-10% bleach, dip the plants for a few minutes as needed to destroy the algae. Make sure they are thoroughly rinsed because bleach can kill your fish. Invest in a filter. Remember, if algae persist through regular water changes, you have to do more to combat the problem.

What naturally kills algae in a fish tank? ›

To decrease aquarium algae naturally, add live plants to your aquarium, like java moss and dwarf lilies, which will take away the nutrients that algae need to grow. You can also try introducing algae-eating fish to your tank, like catfish, bushy-nosed plecos, red cherry shrimp, or ivory snails.

What are methods and steps to control algae in a freshwater tank? ›

Luckily, there are some simple ways to keep algae under control that do not require too much time or effort.
  1. Portion Control. When you feed your fish too frequently, they may not eat it all. ...
  2. Dim the Lights. ...
  3. Go Green. ...
  4. Change Is Good. ...
  5. Know Your Water. ...
  6. Scrape Away. ...
  7. A Helping Hand. ...
  8. Keep Calm & Use Algae Control.
5 Mar 2017

How do you naturally reduce algae? ›

The good news is there are natural ways to get rid of algae in your tank.
  1. Light reduction. This is achieved by reducing the amount of time the light is turned on or by wattage reduction. ...
  2. Food reduction. ...
  3. Frequent water changes. ...
  4. Make sure your filter or protein skimmer are working well. ...
  5. Add natural aquarium cleaners.
1 Feb 2014

What color light stops algae growth? ›

Our results show that algae grows the best under white light and more in blue light than red light. Therefore, our hypothesis is partially supported because the growth rate was higher under the blue light in comparison to the red group; however, the algae under the control condition experienced the most growth.

Why is my fish tank full of algae? ›

Why Does My Fish Tank Have So Much Algae? Algae is caused by an imbalance of nutrients and lighting in your aquarium. This simple statement can be a little difficult to unpack, but basically, your plants need just the right amount of lighting and nutrients for optimal growth.

What stops algae from growing? ›

Add 4 parts of *chlorine to every 1,000,000 parts water - Chlorine also stops algae growth. In this small of a ratio, the water will still be safe to drink or irrigate with.

Do snails eat algae? ›

Most snails are scavengers that dine on algae, dead plant material, dead fish and other detritus, which makes them an excellent option to help you keep your tank clean.

How do I stop my fish tank going green? ›

The most effective and effortless way to get rid of Green Water is to install an Ultra-violet Sterilizer on your aquarium. As water passes through the UV chamber, suspended algae are eliminated, along with many disease-causing organisms. The result is crystal clear water in a matter of days.

Do LED aquarium lights cause algae? ›

Contrary to what you may have been told, LED lights do not cause algae growth any more than other aquarium lighting options. Some LED lights also have adjustable light options to dim or brighten the light according to your fish's needs.

Does CO2 reduce algae in aquarium? ›

Overall, adding CO2 or increasing CO2 in the aquarium can help to reduce algae in your aquarium if you're providing too much light to your aquarium plants.

Do aquarium plants reduce algae? ›

You may have noticed that well-planted aquariums rarely have any algae. That's because aquatic plants remove nutrients from the water and starve out algae. Live plants are one of the most effective ways of preventing algae growth in an aquarium, but it takes more than just one or two to be effective.

Are fish okay with LED lights? ›

How Lighting Affects Fish. Fish are not as reliant on light as plants. In general, aquarium owners can use incandescent, fluorescent, or LED lights for fish but should be aware of the heat issues that incandescent lights cause.

How many hours a day should aquarium light be on? ›

How long should I keep my aquarium lights on? To provide animals and plants the lighting they need, 10 to 12 hours a day is sufficient. Installing a timer or purchasing a unit with integrated timing can make lighting easier––just set it and forget it. Keep in mind algae loves light as well.

Does too much light cause algae in aquarium? ›

Too much light causes more algae growth. Reduce the time the aquarium lights are on to eight hours, or a bit less if necessary, to help reduce the algae growth.

How do I make my fish tank water crystal clear? ›

Table of Contents
  1. Regular Maintenance.
  2. Correct Filtration.
  3. Eradicate Algae From Your Aquarium.
  4. Reduce Nitrates and Phosphates.
  5. Use a Water Treatment or Clarifier.
  6. Reduce Waste in your Tank.
  7. Maintaining Crystal Clear Water.
2 Oct 2020

Is algae bad for fish? ›

While algae are generally harmless, algal blooms, such as blue-green algae, can be toxic to humans, livestock, fish and wildlife.

Does temperature affect algae growth in aquarium? ›

6) Keep Your Tank Cool During Warm Summer Months

In summer months it can be hard to keep your tank cool without breaking the bank, but high temperatures not only pose a risk to fish and coral, they are a sure way to kick off a algae bloom!

Does algae growth mean my tank is cycled? ›

At some point in the process, you'll notice the beginnings of life in your sterile tank, in the form of an algae bloom. This is a sign that the cycle is nearing completion – there are enough nitrates in the tank to support algae. Get your water tested; either do it yourself, or have your LFS test it.

How do you control algae in a 5 gallon tank? ›

Quickly getting rid of algae
  1. Make sure you are not overfeeding your fish and remove any waste food from your tank.
  2. Reduce the light and reduce the amount of algae that can grow. ...
  3. Perform weekly water changes of 10-20% of your aquarium's water.
  4. Clean your tank regularly. ...
  5. Maintain your filter.
26 May 2022

How does algae get into fish tanks? ›

Where does algae come from? Algae spores can be introduced to an aquarium on plant leaves or in fish bag water, but even in aquariums which were set up and totally sterile, with no plants, fish water or other lifeforms, algae can still start to grow.

What will eat fish poop? ›

What Fish Eats Fish Poop. There are several species of fish that are thought to eat the poop or feces of other aquarium inhabitants; some of these so-called poop-eaters are the plecos, corydoras, shrimp, and snails.

What fish cleans the tank? ›

Suckermouthed catfish like Common and Sailfin Plecos, Bristlenose and Otocinclus all graze algae and will “clean” the tank of it, but they do also need food in their own right if they are to grow, stay healthy and thrive.

Why does my fish tank water turn green fast? ›

At the most basic, green aquarium water is caused by tiny bits of algae. These living bits are called phytoplankton, and you can only see them with a microscope. When phytoplankton become too concentrated in your tank, they'll turn the water green, also called an algae bloom.

Why is my fish tank cloudy after 1 day? ›

The cause is usually due to bacterial bloom. As the new aquarium goes through the initial break-in cycle, it is not unusual for the water to become cloudy or at least a little hazy. It will take several weeks to several months to establish bacterial colonies that can clear waste from the water.

How often should I feed my fish? ›

You should feed your fish two to three times daily. A few flakes per fish is sufficient. The fish should eat all the food in two minutes or less. Overfeeding can cloud your water and harm your fish.

Can low light cause algae? ›

The two factors that we must consider are light and nutrients. Light is one of the more perplexing components to algae control, as algae will thrive under low OR high intensities. Without aquatic plants, low light conditions will favor the growth of algae, since there is no competition for the light or other nutrients.

What color light is best for fish tank? ›

8,000K White

This spectrum is ideal for live planted aquariums as it mimics shallow water conditions and usually produces higher PAR (ppfd) for stronger plant growth.

Can a light be too bright for fish? ›

Again, depending on the kind of fish you have, you'll want to think about color temperature. But in general, the lighting shouldn't be too bright for a regular tank since it could stress the fish. Too-bright lighting can also lead to algae growth.

What fish eats a lot of algae? ›

Saltwater. Some of the known types of fish to eat algae are Blennies and Tangs, but along with fish there are snails, crabs, and sea urchins who also eat algae. These species are known to eat red slime algae, green film algae, hair algae, diatoms, cyanobacteria, brown film algae, detritus, and microalgae.

Will algae eaters eat fish? ›

Also as they mature, they seek more and more of a “meaty” diet, so will often prefer flake or tablet food rather than algae. There are even reports of large specimens attacking and eating other fish.

Do guppies eat algae? ›

The answer is yes, they eat algae, and they are very good at it. However, algae don't make up a complete diet. Guppies still need insects, invertebrates, and also fish fry to survive. If we take a look at the algae part of the diet, we can see that guppies get plenty of protein and additional nutrients from algae.

How long can algae live without light? ›

Since algae are photosynthetic organisms, they need light to grow and survive. By blocking out the light to an aquarium tank for four to seven days, most algae will be completely eliminated. Although algae need light to live, they are still much hardier than you would think.

Does algae grow in sand? ›

Algae typically grows on structures before it invades the sand bed. To get the silicate levels down you can run a phosphate remover (most remove silicates so read the label first). Its also important to use pure water with TDS readings as close to zero as possible.

Does carbon get rid of algae? ›

Some algae is easy to remove. All you need to do is scrub. To help keep water clean, use of a premium grade carbon will help reduce dissolved organics and slow the return of algae.

Can too much CO2 cause algae? ›

The good news is, YOU DO NOT have to experience algae in your planted aquarium. Algae normally appears when there is an imbalance in nutrients, CO2, oxygen and light. For example, too much light but too few nutrients and CO2 will cause algae. Poor distribution of CO2 and nutrients is also a common cause of algae.

Will algae go away on its own? ›

The rapid growth of algae over a patch of water is known as an algal bloom. Algae can vanish on its own if they do not get the required nutrition. However, Algae can also be removed by algaecides or other water treatments such as chlorination.

How much algae is too much? ›

"Today the EPA confirmed what we know to be true: that is extraordinarily dangerous to human health. The EPA has now stated that it is unsafe at any level above 8 parts per billion.

How do I get rid of algae in my fish tank glass? ›

An easy way to remove algae from your glass is an aquarium scraper and some elbow grease. The scraper will remove large algae deposits, as well as daily film algae, leaving you with a clear view of your fish. But make sure to get into every nook and cranny!

Will algae go away on its own? ›

The rapid growth of algae over a patch of water is known as an algal bloom. Algae can vanish on its own if they do not get the required nutrition. However, Algae can also be removed by algaecides or other water treatments such as chlorination.

How do I stop my fish tank going green? ›

The most effective and effortless way to get rid of Green Water is to install an Ultra-violet Sterilizer on your aquarium. As water passes through the UV chamber, suspended algae are eliminated, along with many disease-causing organisms. The result is crystal clear water in a matter of days.

Do snails eat algae? ›

Most snails are scavengers that dine on algae, dead plant material, dead fish and other detritus, which makes them an excellent option to help you keep your tank clean.

How do you clean a fish tank without removing the fish? ›

How to: Clean Aquarium Without Removing Fish - YouTube

Why is my fish tank always green? ›

Fish tanks turn green with algae, which need light, water and nutrients to grow. Algae spores are airborne, so even if you start off with brand new everything, coldwater, tropical or marine, your tank will go green.

How long does it take for algae to go away? ›

Most toxins are degraded within 2 weeks, but can be in the water at low levels for many months after a bloom forms.

How long can algae live without water? ›

Under controlled laboratory conditions, unicellular green algae from biological soil crusts in the desert can survive for at least 4 weeks (Gray et al., 2007). In this study, desiccation-tolerant desert algae and closely related aquatic relatives were exposed to dry conditions.

Why are the rocks in my fish tank turning brown? ›

Aquarium gravel turns brown because of brown algae bloom in the tank. Brown algae grow due to excessive levels of silicates, nitrates, and phosphorus in the tank water. They also grow because of poor lighting, inefficient filtration system to clean the aquarium water, and irregular tank maintenance.

What fish eats a lot of algae? ›

Saltwater. Some of the known types of fish to eat algae are Blennies and Tangs, but along with fish there are snails, crabs, and sea urchins who also eat algae. These species are known to eat red slime algae, green film algae, hair algae, diatoms, cyanobacteria, brown film algae, detritus, and microalgae.

What animal cleans a fish tank? ›

Plecostomus

They gobble up algae and anything else they find at the bottom of a tank. In the aquarium world they are known as 'janitor fish' for their supreme algae cleaning abilities. If a Goldfish tank has an algae problem, you will usually spot a Common Pleco at the bottom.

Will algae eaters eat fish? ›

Also as they mature, they seek more and more of a “meaty” diet, so will often prefer flake or tablet food rather than algae. There are even reports of large specimens attacking and eating other fish.

Do LED lights cause algae growth? ›

Contrary to what you may have been told, LED lights do not cause algae growth any more than other aquarium lighting options. Some LED lights also have adjustable light options to dim or brighten the light according to your fish's needs.

Why is my fish tank cloudy after 1 day? ›

The cause is usually due to bacterial bloom. As the new aquarium goes through the initial break-in cycle, it is not unusual for the water to become cloudy or at least a little hazy. It will take several weeks to several months to establish bacterial colonies that can clear waste from the water.

How often should I feed my fish? ›

You should feed your fish two to three times daily. A few flakes per fish is sufficient. The fish should eat all the food in two minutes or less. Overfeeding can cloud your water and harm your fish.

Videos

1. 10 Types of Algae Commonly Found In Planted Aquariums and How to Control It
(G N J's Aquatic Nation)
2. Get rid of algae once and for all. Not just control but beat algae in the reef tank.
(BRStv - Saltwater Aquariums & Reef Tanks)
3. How to get rid of all types of algae in SECONDS in your aquarium!
(MasterAquatics)
4. How to remove Black Beard Algae from your aquarium
(Big Fish Little Fish Aquatics)
5. How to FIGHT ALGAE in 11 Easy Steps
(Girl Talks Fish)
6. Hair Algae in Aquarium! THE ALGAE GUIDE EPISODE #6
(MJ Aquascaping)

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